Wellburn Interchange is junction 10 of the M74.
Built in 1986 as part of the first southern extension of the M74 (see M74 and A74(M) History), Wellburn Interchange is junction 10 of the M74. The junction is a dumbbell junction with the B7078 crossing over the top of the motorway. However, there is a slip road missing, with the M74 southbound off slip missing, this movement being served by the single slip Junction 9.
To the north the B7078 is simgle carriageway, but to the south of the junction, the B7078 heads into Lesmahagow, quickly becoming dual carriageway as the route picks up the old A74. This is the start of the longest surviving section of dual carriageway from the old road, albeit hardly changed since the motorway opened, meaning that the surface is old and worn, but otherwise gives a good taste of what the old A74 was like.